Power transmission



June 1969 R. B. PETTIBONE 3,447,477

POWER TRANSMISSION Filed June 22, 1967 INVENTOR. 4 RAYMOND a. PYETTIBONEUnited States Patent 3,447,477 POWER TRANSMISSION Raymond B. Pettibone,Detroit, Mich., assignor to Sperry Rand Corporation, Troy, Mich., acorporation of Delaware Filed June 22, 1967, Ser. No. 648,161 Int. Cl.F04c 1/16; F02b 53/00 US. Cl. 103136 11 Claims ABSTRACT OF THEDISCLOSURE A fluid energy translating device of the sliding vane typehaving a stator with high pressure and low pressure passages and a vanetrack with a rotor rotatably mounted within the track and encasedbetween two cheek plates; the rotor having a plurality of radial steppedslots with a vane and pivotal thrust member assembly slidably mountedtherein and which form separate expansible pressure'chambers in eachslot which, when filled with a pressure fluid, will provide an outwardforce for maintaining the vanes in contact with the vane track.

A pressure porting arrangement in each cheek plate which permits highpressure fluid to enter, from both sides of the rotor, the expansiblepressure chambers in those slots associated with the vanes which aretraversing the low pressure passages of the device; the same expansiblechambers exhausting fluid into a blind port in each cheek plate forcingfluid to flow into the running clearance between the rotor and cheekplate faces when the vanes are traversing the high pressure passages ofthe device for creating a pressure in the same chambers greater thanthat existent in the high pressure passages resulting in a favorableunbalanced outward force for maintaining the vanes in contact with thevane track and for minimizing rotor-cheek plate contact by equalizingthe pressure in the running clearance between the rotor and cheek platefaces.

BACKGROUND OF THE INVENTION This invention relates to powertransmissions and is particularly applicable to those of the typecomprising two or more fluid pressure energy translating devices, one ofwhich may function as a pump and the other as a fluid motor. Moreparticularly, this invention relates to an improvement in sliding vanetype pumps and motors such as illustrated in the patent to Harry F.Vickers No. 1,989,900.

In units of this type, it has been a conventional practice to transmithigh pressure to the full underside of the vanes so as to maintain thevanes in contact with the vane track. One of the limiting factors in thelife of such units is the excessive wear rate between the vanes and thevane track under excessive operating conditions. This is due to the factthat the vanes traversing the suction ramp are completely unbalancedhaving only low pressure on their outer ends while the inner ends arecontinuously subjected to high pressure.

Although a certain amount of wear is permissible without destroying theefiiciency of the pump, when certain limiting speeds and pressures areexceeded the wear rate is so great as to be economically unfeasible.

Because of this limitation, other constructions have been designed whichconnect the high pressure side of the device to the inner ends of thevanes only 'on the high pressure or discharge phase thereof, and whichconnect the low pressure side of the device to the inner ends of thevanes during the low pressure or suction phase. While this has proved tobe a relatively effective device, practical considerations have resultedin a maximum operating speed. At higher speeds the vanes becomeimproperly balanced and not only is the volumetric efliciency of thedevice decreased, but likewise its pumping capacity. As the speed of thedevice increases, the centrifugal force urging the vanes against thetrack increases, but this advantage is overcome by an increased pressuredifferential tending to separate the vanes from the track. As the speedof the rotor increases the pressure differential required to cause thevanes to pump the fluid out increases and at certain higher speedsbecomes so great that the vanes are unbalanced inwardly and move awayfrom the track.

Still other types of devices have been designed to provide a properunbalanced condition to meet the requirements of a very high speed andpressure operation. This is. accomplished by having an intermediatepressure chamber associated with a relatively smaller pressure effectivesurface on each vane in addition to the chambers associated with theinner ends of the vanes, and by providing a pressure transmittingporting arrangement to both chambers such as illustrated in the patentsto Duncan B. Gardiner Nos. 2,967,488 and 2,919,651.

Another of the limiting factors in the service life of such units is thedevelopment of localized wear points between the vanes and the walls ofthe slots in which they are carried. This is due in part to the severebending moment produced on the vanes by a pressure diiferentialthere-across when the vanes are in an extended position. Theconventional construction utilized in the past has provided a vane ofsubstantially uniform thickness to engage the sides of the vanereceiving slot and extending therefrom to engage the vane track. Inpumps utilizing the conventional construction, there has been notedexcessive Wear of the vane track, the rotor, and the individual vanes.This surface disturbance interrupts the smooth contour of the track tocause noisy and ineflic'ient operation. Further, unless the conventionalvanes are carefully fitted to the vane slots, internal leakage in suchunits may exceed acceptable limits.

Because of this limitation, other constructions have been designed tominimize the heretofore noted wear, such as illustrated in the patent tome No. 2,821,143. This design, while advantageous, does not support allfrontal tangential forces imposed upon the vane, thus permitting contactstress between the vane and rotor segment at the lower end of the vane,resulting in deterioration of the vane and slots during very highpressure and speed operation.

Another of the limiting factors in the service life of such units is thepremature deterioration of the face of the rotor and cheek plate whenoperated at extremely high speeds and pressures. As illustrated in theherebefore mentioned Gardiner patents, pressurized fluid is transmittedfrom the pressure plate through the rotor intermediate chambers to portson the opposite side of the rotor whereupon fluid flows into the spacebetween the rotor and wear plate and thus providing a fluid film forpreventing rotor 'and wear plate contact. At extremely high speed andpressure operation, there is a notable pressure drop across the rotorcausing the rotor to shift toward and to come into contact with the wearplate resulting in noise and undue wear.

SUMMARY This invention comprises a rotary fluid energy translatingdevice of the sliding vane type having in combination a plurality ofstepped slots and vanes with a thrust member mounted for pivotalmovement between each vane and slot with means forming separate pressurechambers in each slot, one of which is associated with a pressureresponsive surface on the thrust member, the other associated with apressure responsive surface on the vane, and means forming a pressuretransmitting porting arrangement to both chambers, the said surfacesbeing effective under pressure to urge the vanes into engagement withthe track.

It is an object of the invention to provide a fluid energy translatingdevice of the sliding vane type having an improved vane biasingarrangement.

It is another object of this invention to provide a fluid energytranslating device having an improved vane structure and vane biasingarrangement which reduces wear between the vanes and the guiding slots.

It is still another object of this invention to provide a fluid energytranslating device having dual pressure chambers associated with eachvane and an improved pressure transmitting arrangement associatedtherewith which assures proper rotor balance at high pressure and highspeed operation and which reduces noise and wear between the rotor andcheek plates.

It is a further object of this invention to provide a fluid energytranslating device of the sliding vane type having means for providing acontrolled, safe, and efficient differential therein for urging the vanein contact with the vane track.

It is also an object of the invention to provide a fluid energytranslating device of the sliding vane type which is of low cost,eflicient, quiet, and long wearing.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being made to the accompanyingdrawing wherein a preferred form of the present invention is clearlyshown.

In the drawing:

FIG. 1 is a longitudinal sectional view of a fluid energy translatingdevice embodying a preferred form of the present invention and taken online 1-1 of FIG. 2.

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1.

FIG. 3 is a sectional view 33 of FIG. 1.

FIG. 4 is a partial sectional view taken on the line 44 of FIG. 3.

FIG. 5 is an enlarged partial sectional view of the vanes as illustratedin FIG. 2.

Referring now to FIGURES 1, 2, and 3, there is shown a rotary fluid pumpindicated by the numeral 10, the

housing of which comprises a cam ring section 12 sandwiched between abody section 14 having a wear plate 16 and an end cover 18, all of whichare suitably connected to each other by bolts 20. The body section 14 isprovided with an inlet supply connection port 22 having an inlet passage24 leading therefrom which is branched and terminates in a pair of fluidopenings, one of which is shown in FIG. 1, registering with duplicateopposed fluid openings 26 and 27 extending through the wear plate 16 andwhich are shown in FIG. 3.

An outlet connection port 28 is located in the end cover 18 which leadsdirectly from a pressure delivery chamber 30 formed in an enlarged bore32 of the end cover 18 where a pressure plate 34 is fioatably mounted inthe bore 32. The pressure plate 34 and wear plate 16 are each formedwith a flat surface indicated, respectively by the numerals 36 and 38which abut opposing flat faces 40 and 42 of the cam ring 12 and providefluid sealing engagement for the immediately adjacent faces of rotor 44mounted within the cam ring 12. The pressure plate is adapted to beurged against a portion of the flat face 40 of the cam ring 12 and influid sealing engagement with the rotor by pressure in the pressurechamber 30. A spring 45 initially biases the pressure plate toward therotor until pressure builds up in the pressure chamber.

The rotor 44 is driven by a shaft 46 provided with a seal 47, andextends from the body for connection to a prime mover, not shown. Theshaft is spline connected to the rotor at 48 and is rotatably mounted inbearing 50 and 52, in the body 14. O-ring seals 54 and 56 preventleakage at the juncture of the end cover 18 and the wear plate 16 withthe cam ring 12 while an O-ring seal 58 4 prevents leakage at thejuncture of the body 14 and the wear plate 16.

The inner surface of the cam ring 12 forms a cam track substantiallyelliptical in shape, indicated by the number 60, against which the outertips 62 of vanes 64, the latter of which are slidably mounted in slots66 of the rotor 44, are adapted to be maintained in contact. The camtrack contour and the outer periphery of the rotor define two opposedworking chambers, indicated by the numerals 68 and 70, each of which,for the purposes of convenience, may be divided into a fluid inlet zone,and a fluid delivery zone. The fluid inlet zones are those portions ofthe working chambers 68 and 70 registering with the opposed fluid inletopenings 26 and 27 in the wear plate 16. The fluid delivery zones arethose portions of the working chambers 68 and 70 registeringrespectively with opposed arculate fluid delivery ports 72 and 74 in thepressure plate 34, shown as dotted lines in FIG. 2 which are connectedto the pressure chamber 30 by means of duplicate passage 75 leadingtherefrom, one "of which is shown in FIG. 1.

The fluid inlet ports 26 and 27, which extend completely through thewear plate 16, are also duplicated respectively by mirror image ports 76and 78 in the face 36 of the pressure plate; and fluid delivery ports 72and 74 in the pressure plate 34 are also duplicated respectively bymirror image pressure ports 80 and 82 in the face 38 of the wear plate16 to produce filling and balance on opposite sides of the rotor.

The vane track 60 includes an inlet Zone ramp extend- :ing from a to b,a true arc portion extending from b to c, a delivery Zone ramp extendingfrom c to d, and another true are portion extending from d to e. Thetrack is symmetrical about both its major and minor axes, thus each ofthe ramps and true arc portions from a to e are duplicated in the lowerportion of the track. As the ends of the vanes traverse the inlet ramps,the vanes move radially outward with respect to the rotor, and while thevane ends traverse the delivery ramps, the vanes move radially inward.In the true are portions, the vanes partake of no radial movement.

The inner ends of the vane slots 66 are enlarged to form with the innerends 84 of the vane 64, enclosed undervane pressure chambers 86 whichundergo cyclic contraction and expansion during rotation of the rotor.

A slipper 88 which, as later explained, performs the function of athrust member is essentially a half round rod equal in length to the vanwidth and is mounted in the vane 64 in a mating half round groove 90which performs the function of a socket in the vane 64 for providingpivotal movement relative thereto. Each slipper has a flat outer endsurface 92 and a pressure responsive intermediate surface 93, the flatouter end surface being extended out from the vane for slidable abutmentwith a side wall 65 in each slot 66. The wall 65 of each vane slot 66 isformed with a stepped portion indicated by the numeral 94 which togetherwith the intermediate slipper surface 93, forms in each slot an enclosedintermediate expansible pressure chamber 96. The intermediate chamber 96opens exteriorly to each side face of the rotor while undergoing cyclicexpansion and contraction as the rotor revolves.

Although the preferred form of the invention is shown with a singleslipper vane combination in each slot, two slippers may be utilized witheach vane in each slot to achieve the desired unbalanced outward forcetherein.

Such a construction is illustrated by the dotted lines in FIG. 5 whereina slipper 88a is pivotally mounted at one end in the vane 64 and at itsother end is slidably abutting a wall of slot 66 in which an expansiblechamber 96a is formed between an intermediate pressure responsivesurface 93a and a step 94a. The dual slipper vane construction willfunction in the same manner as the single slipper vane construction asdescribed herein.

In the form of device illustrated, a flow path is formed connecting thehigh pressure side of the device to the expanding intermediate chambers.The flow path is formed by providing diametrically opposed ports 98 inthe face 38 of the wear plate which are adjacent to the inlet ramps andtrue are portions and are connected to the pressure ports 80 and 82 bydrilled passages 181 and 102 and 104 (as shown in FIGURES 3 and 4). Theports 98 are also duplicated by pressure ports 106 in the face 36 of thepressure plate 34 and are connected to the pressure chamber 30 bydrilled passages 108. The pressure chamber 30 thus forms with thepressure plate outlet or delivery ports 72 and 74 and passages 75 acontinuous outlet passage leading to the outlet port and also form withthe diametrically opposed ports 98 and 106 a flow path for connectingthe high pressure side of the device to the expanding intermediatechambers. There is also provided diametrically opposed blind ports 110in the wear plate face 38 and diametrically opposed blind ports 112 inthe pressure plate face 36; the ports being adjacent the outlet ramps,the purpose of which is explained hereafter.

The vanes traversing the inlet ramp 0-]; and it duplicate inlet ramp areextending causing an expansion of their associated intermediate chambers96. The intermediate chambers of the extending vanes are incommunication with the diametrically opposed ports 98 and 106 during thevane extending phase and high pressure fluid will flow from ports 98 and106 to fill these chambers. Simultaneously, the vanes, which aretraversing the outlet ramp 0-11 and its duplicate outlet ramp, areretracting, causing a contraction of their associated intermediatechambers 96, and the same chambers will displace pressure fluid into thediametrically opposed blind ports 110 and 112.

During the discharge phase of the device, the blind ports, from whichfluid can flow only into the running clearance formed between the rotorside faces and the face surfaces of the opposed cheek plates 16 and 34,are adapted to create a pressure in the intermediate chambers which isgreater than the pressure existent in the fluid outlet zone throughwhich the outer ends of the vanes pass.

As explained hereafter, the pressure in the fluid delivery zones and theassociated inner vane chambers are equal, therefore, the higher pressureproduced in the intermediate chambers will result in a favorableunbalanced outward force for maintaining the vanes in contact with thevane track during the discharge phase. The effective area of the exposedintermediate surface 93 of the slipper 88 is preselected to create aresultant force sufiicient to maintain the tip of the vanes in contactwith the vane track during all phases in a cycle of the device, but lowenough top revent excessive ring wear during the suction phase.

As hereinbefore mentioned, the excess fluid, which is exhausted from theintermediate chamber into the blind ports during the discharge phase,will flow into the running clearance between the adjacent faces of thepressure plate, rotor, and wear plate for providing a film of fluid onboth sides of the rotor. With fluid being fed into the chambers at bothfaces of the rotor, the aforesaid unfavorable condition of a pressuredifferential across the rotor is eliminated, thus permitting the rotorto center itself between the pressure plate and the Wear plate.

For the purpose of equalizing the pressure in the inner and outer endsof the vanes, the rotor is provided with a plurality of angular drilledpassages 114, one for each vane slot, which lead from the periphery ofthe rotor, between the vanes to the enlarged chambers 86 at the innerend of each vane slot. The outer end of each v-ane is constructed with atrailing taper 116 and a relatively small leading taper 118 to form thetip 62 which as aforementioned is adapted to contact the vane track. Theouter surface of the vanes comprising the tappers 116 and 118 areexposed to the pressures in the expanding and contracting intervanespaces and by means of the angular passages 114, the cyclically changingintervane pressure is conducted to the inner chambers 86.

In order to facilitate filling of the undervane chambers 86 during thesuction stroke and during high speed operation, the wear plate 16 isalso provided with auxiliary inlet ports and 122 which are connected tothe inlet passage of the body device, and the spacing between the shaftand rotor by slots 124 and 126. Duplicate auxiliary inlet ports 128 and130 are provided in the face of the pressure plate adjacent the rotor,and are connected respectively by means of slots 132 and 134 to a recess136 in the pressure plate. Inlet fluid is therefore conducted from theauxiliary inlet porting in the wear plate side of the device through themedium of the spacing between the shaft and rotor splining to the recess136, and by means of slots 132 and 134, to the duplicate auxiliary ports128 and 130 of the pressure plate. Dowel pins 138 are utilized toprovide proper alignment of the porting located in the Wear and pressureslots with the working chambers of the device.

The system pressure imposed on the slipper 88 forces it into contactwith the vane to take up any excess or free clearance, permitting arelaxation of the vane and rotor slot machining tolerances. The relativepivotal motion of the slipper 88 and vane 64 provides a mechanical sealwhich not only reduces the leakage between the intermediate chambers andthe Working chambers, but it eliminates the need for closevane-slipper-step slot dimensions.

The relative pivotal motion of the slipper and vane also permits theslipper to act as a self-aligning bearing pad for compensating for vanetilt thus reducing rotor vane contact stress resulting from theaforementioned bending forces imposed on the vane.

Devices embodying the invention operate at much higher pressure andspeeds than conventional devices of the type herebefore mentioned, yetminimizes excessive wear rate While providing utmost efiiciency and longlife.

While the form of the embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adapted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. In a rotary fluid energy translating device of the sliding vane typeincluding low and high pressure operating passages, one of which is aninlet passage and the other an outlet passage, and a vane track;

a rotor having means forming a plurality of stepped slots and rotatablewithin the track;

a plurality of vanes slidably mounted within said slots, the outer endsof which are adapted to engage the track;

a plurality of thrust members mounted between said slots and said vanesfor pivotal movement relative thereto, each vane and each thrust memberhaving a surface thereon effective under pressure to urge the vanestoward the track;

means forming separate pressure chambers in each slot, one of which isassociated with the thrust member surface, the other associated with thevane surface;

and passage means connecting the high pressure operating passage of thedevice to at least one of said separate pressure chambers for aidingcentrifugal force in maintaining the outer ends of the vanes inengagement with the vane track.

2. In a rotary fluid energy translating device of the sliding vane typeincluding low and high pressure operating passages, one of which is aninlet passage and the other an outlet passage, and a vane track having alow pressure and high pressure ramps;

a rotor having means forming a plurality of stepped slots and rotatablewithin the track;

a plurality of vanes slidably mounted within said slots, one end of eachvane being adapted to abut the track and the intervane spaces undergoingalternate phases of expansion and contraction as the vanes traverse thevane track ramps during a cycle of the device;

a plurality of thrust members mounted between said slots and said vanesfor pivotal movement relative thereto, each vane and each thrust memberhaving a surface efiective under pressure to urge the vanes toward thetrack;

means forming separate pressure chambers in each slot, one of which isassociated with the thrust member surface, the other associated with thevane surface;

means for porting the cyclically changing intervane pressure to one ofsaid chambers in timed relation with the expansion and contractionphases of the intervane spaces;

and passage means connecting the high pressure passage to the other ofsaid chambers during the intervane expansion and contraction phases ofthe device.

3. A combination as in claim 2 including a restricted flow path in saidpassage means connecting the high pressure passage to the said otherchambers during the intervane contraction phases of the device forcreating a pressure in said other chambers during said contraction phasewhich is greater than is existent in the high pressure passage.

4. In a rotary fluid energy translating device of the sliding vane typeincluding low and high pressure operating passages, one of which is aninlet passage and the other an outlet passage, and a vane track having alow and high pressure ramp;

a rotor having means forming a plurality of stepped slots and rotatablewithin the track;

a plurality of vanes slidably mounted within said slots wherein an outerend of each vane is adapted to abut the track and the intervane spacesundergoing alternate phases of expansion and contraction as the vanestraverse the vane track ramps during a cycle of the device;

a plurality of thrust members mounted between said slots and said vanesfor pivotal movement relative thereto, wherein each vane and each thrustmember respectively have a vane end surface and a thrust member surfaceand each vane and each thrust member respectively form an end pressurechamber and an intermediate pressure chamber in each slot, the saidsurfaces being effective under pressure in said chambers to urge theouter ends of the vanes in engagement with the track;

means for porting the cyclically changing intervane pressure to the endchambers in timed relation with the expansion and contraction phases ofthe intervane spaces;

and passage means for connecting the high pressure passage to theintermediate chambers.

'5. A combination as in claim 4 including said plurality of slots withmeans forming a step in each Wall therein;

and said thrust members being mounted on opposite sides of each vanebetween the vane and slot wall for pivotal movement relative thereto.

6. In a rotary fluid energy translating device of the sliding vane typeincluding low and high pressure operating passages, one of which is aninlet and the other an outlet passage, and a vane track having inletpressure and outlet pressure ramps;

a rotor having means forming a plurality of stepped slots and rotatablewithin the track;

means forming two cheek plates, said rotor being disposed between saidcheek plates, there being a running clearance between said cheek platesand rotor;

a plurality of vanes slidably mounted within said slots, one end of eachvane being adapted to abut the track and the intervane spaces undergoingalternate phases of expansion and contraction as the vanes traverse thevane track ramps during a cycle of the device;

a plurality of thrust members mounted between said slots and said vanesfor pivotal movement relative thereto, each vane and each thrust memberhaving a surface efi'ective under pressure to urge the vanes towards thetrack; means forming separate pressure chambers in each slot, one ofwhich is associated with the thrust member surface, the other associatedwith the vane surface;

passage means for connecting the cyclically changing intervane pressureto only one of said separate pressure cham ers in each slot in timedrelation with the expansion and contraction phases of the intervanespaces;

means connecting the high pressure operating passages simultaneouslythrough both cheek plates on opposite sides of said rotor to the otherof said pressure chambers in each slot as the vanes traverse the lowpressure ramp; and

means forming blind ports in each of said cheek plates on opposite sidesof the rotor, said ports registering with said other pressure chambersas the vanes traverse the outlet pressure ramp, the only outlet from theblind ports being the said running clearance on opposite sides of therotor, and creating a pressure in said other chamber greater than isexistent in the high pressure passage for providing a favorableunbalanced outward force for maintaining the vanes in contact With thevane track and also for equalizing the pressure on opposite sides of therotor in said running clearance.

7. In a rotary fluid energy translating device of the sliding vane typeincluding low and high pressure operating passages, one of which is aninlet passage and the other an outlet passage, and a vane track havinginlet and outlet pressure ramps;

a rotor having means forming a plurality of slots and rotatable withinthe track;

means forming two cheek plates, said rotor being disposed between saidcheek plates, there being a running clearance between said check platesand rotor;

a plurality of vanes slidably mounted within said slots,

one end of each vane being adapted to abut the track and the intervanespaces undergoing alternate phases of expansion and contraction as thevane traverse the vane track ramps during a cycle of the device;

means forming separate surfaces associated with each vane, said surfacesbeing elfective under pressure to urge the vanes towards the track;

means forming separate pressure chambers in each slot one of which isassociated with one of said surfaces, the other associated with theother of said surfaces; means for connecting the cyclically changingpressure to one of said separate chambers in each slot in timed relationwith the expansion and contraction phases of the intervane spaces;

means connecting the high pressure operating passages simultaneouslythrough both cheek plates on opposite sides of said rotor to the otherof said pressure chambers in each slot as the vanes traverse the lowpressure ramps;

and means forming blind ports in each of said cheek plates on oppositesides of the rotor, said ports registering with said other pressurechambers as the vanes traverse the outlet pressure ramps, the onlyoutlet from the blind ports being the said running clearance on oppositesides of the rotor and creating a pressure in said other chamber greaterthan is existent in the high pressure passage for providing a favorableunbalanced outward force for maintaining the vanes in contact with thevane track and also for equalizing the pressure on opposite sides of therotor in said running clearance.

8. As a new article of manufacture slidable in a rotor slot havingparallel side walls with a step formed therein, a vane and thrust memberassembly comprising:

a fiat vane, substantially rectangular in cross section,

constructed with a groove forming a socket located in a flat surface ofthe vane betwen an outer end surface and an inner end surface;

a thrust member having a flat outer end surface and a half round innerend surface, the inner end surface being disposed within the vane socketfor pivotal movement relative thereto, the flat outer end surface beingextended beyond the flat vane surface and adapted to engage a side Wallof the slot and provide a surface effective under pressure for aidingcentrifugal force is extending the vane.

9. As a new article of manufacture for use Within a vane track of afluid energy translating device:

a rotor having a plurality of substantially radial slots with parallelside walls extending from the periphery of the rotor with a step formedin a wall in each slot, each slot having an enlarged pressure chamberformed at the inner end thereof;

a fiat, substantially rectangular vane slidable in each slot, each vanehaving a track engaging outer end surface and an inner end surface saidinner end surface being located at the pressure chamber end of the slot;

a substantially half round groove located in the fiat surface of thevane between the outer end surface and the inner end surface;

a thrust member having a substantially flat outer end surface, apressure responsive intermediate surface, and a half round inner endsurface the inner end surface being disposed within each vane groove forpivotal movement relative thereto, the flat outer end surface of eachmember being extended beyond the flat vane surfaces for slidableabutment with a side Wall of each slot to form an intermediateexpansible chamber between each stepped portion of each slot and eachthrust member intermediate surface, the

face, and adapted to engage a side wall of the slot and provide asurface effective under pressure for aiding centrifugal force inextending the vane.

11. As a new article of manufacture for use Within a vane track of afluid energy translating device:

a rotor having a plurality of substantially radial slots with parallelwalls extending from the periphery of the rotor with a step formed ineach wall of each slot and having enlarged pressure chambers formed atthe inner ends of each slot;

a fiat substantially rectangular vane slidable in each slot, each vanehaving a track engaging outer end surface and an inner end surface, saidinner end surface being located at the pressure chamber end of the slot;

a substantially half round groove located in each flat surface onopposite sides of the vane between the outer end surface and the innerend surface;

a thrust member having a substantially fiat outer end surface, apressure responsive intermediate surface and a half round inner endsurface, the inner end surface being disposed within each vane groovefor pivotal movement relative thereto, the flat outer end surface ofeach member being extended beyond the flat vane surface for slidableabutment With the side Walls of each slot to form an intermediateexpansible chamber between each stepped portion of each slot, and eachthrust member intermediate surface, the said intermediate chambers eachopening exteriorly to at least one side of the rotor;

and a separate passage for each vane slot extending from the peripheryof the rotor to the inner pressure chambers of the vane slots.

References Cited UNITED STATES PATENTS said intermediate chambers eachopening exteriorly t H at id fth rotor 2,919,651 1/1960 Gardiner 103-436I e S f f ea 13 vane slot Xten'din 2,962,973 12/1960 Pettibone 103-136an Para Pa age r c e g 3,081,706 3/1963 Drutchas et al. 103136 from theperiphery of the rotor to the inner pressure 40 3 261 334 7/1966 Pa hk vhambers of the vane slots. Sc A I f f t d M Om 3,277,873 10/1966Brodbeck et a1.

a new a f 0 8 1 a e r r 3,326,454 6/1967 DB Castelet 230-145 slot havingparallel side walls with a step formed 1n each Wall, a vane and thrustmember assembly comprising: FOREIGN PATENTS a fiat vane, substantiallyrectangular in cross section 45 993,574 5/1965 Great Britain.

having means forming a socket located in each flat surface on oppositesides of the vane between an outer end surface and the inner endsurface;

a thrust member having a fiat outer end surface and a half round innerend surface, the inner end surface 50 being pivotally disposed withineach vane socket for pivotal movement relative thereto, and the flatouter end surface being extended beyond the flat vane sur- ROBERT M.WALKER, Primary Examiner. WILBUR J. GOODLIN, Assistant Examiner.

US. Cl. X.R.

